2000 Toyota Avalon Catalytic Converter

We don't get involved with costs here because there's way too many variables. In this case we have no idea what parts you're referring to. You didn't list any symptoms or problems you're trying to solve. You didn't say what your mechanic is recommending or is going to do. According to your math, the labor is expected to be $1000.00. That's outrageous for some repairs and way too low for others.